GIL running temperature appraisal procedures in a kind of corridor pipe
Technical field
The present invention relates to the transmission of electricity of extra-high voltage electrical, gas-insulated transmission line (GIL) thermal characteristics, long range extra-high voltage GIL
The fields such as equipment thermal reliability, more particularly to GIL running temperature appraisal procedures in a kind of corridor pipe.
Background technology
Gas-insulated transmission line (GIL) is a kind of using long-distance electricity transmission device of the gas as dielectric, with biography
System cable power transmission is compared, and has the advantages that capacity is big, and loss is low, and service life is long.Common GIL failures are as discharged, insulator
Phenomena such as breakdown is all accompanied by conductor or abnormal skin temperature when occurring.Moreover, GIL bus temperatures are excessive also occurs that
Busbar vault, or even the failure such as disc insulator rupture, basin marine glue cracking.Heat of the research of GIL thermal characteristics to raising GIL
Reliability and guarantee GIL safe and stable operations are of great significance.It is at this stage to use finite element method to GIL thermal characteristics more
Studied, but finite element simulation method is computationally intensive, generally cannot function as subprogram and is embedded into GIL temperature monitoring systems
In.
Therefore, the proposition one kind how innovated fast and effectively in corridor pipe GIL running temperatures appraisal procedure to meet reality
The demand of application is the most important thing.
The content of the invention
The technical problems to be solved by the invention are that solving existing finite element numerical simulation computational methods quick cannot obtain
GIL running temperatures in corridor pipe, and the problem of subprogram is embedded into GIL real-time temperature test sytems is cannot function as, so that
It is proposed GIL running temperature appraisal procedures in a kind of corridor pipe, the thermal characteristics of GIL is solved using analytic method, can not only
Quickly GIL thermal characteristics problems are solved, subprogram is alternatively arranged as and is embedded into GIL temperature monitoring systems.GIL is run
The quick of temperature grasps the thermal reliability for being more conducive to improve GIL and more preferably ensures GIL safe and stable operations, and this method can also be made
It is embedded into for subprogram in GIL real-time temperature test sytems.
To solve the above problems, the technical scheme is that:
GIL running temperature appraisal procedures, comprise the following steps in a kind of corridor pipe:
Step S1:GIL physical models are established, model is related to resistance joule heat effect, the free convection layer of outside air
Stream flowing forces turbulent convection, built-in electrical insulation gas (such as SF6Gas) electricity such as the Laminar Flow of free convection, radiant heat transfer,
Heat, stream, solid multiple physical field, are a multiple physical field coupling models.Therefore GIL running temperature parameters refer in this model evaluation corridor pipe
Mark is included between convection current heat output and thermal exposure, shell and air between joule heat waste, conductor and the shell of conductor and shell
Convection current heat output and thermal exposure.
Step S2:The loss of conductor initial power is calculated, according to above-mentioned physical model, is related to the fluid and solid material of calculating
Matter attribute considers the change with local temperature, i.e. outside air, built-in electrical insulation gas, conductor and enclosure material thermal physical property parameter
It is the function formula of temperature, the enclosure material thermal physical property parameter includes viscosity, and the coefficient of conductivity is permanent than pressing, than
Thermal capacitance, thermal coefficient of expansion, so that the numerical value of hot Physical Parameters is closer to operation actual conditions when calculating;In actually solving
According to the thermal physical property parameter and skin effect coefficient of conductor, the initial temperature of conductor is determined, it is assumed that initial temperature and environment temperature
It is equal, iterative solution under GIL pipelines startup operating condition is calculated according to given initial duty parameter and goes out corresponding public condition lower conductor
Heat amount;
Step S3:The loss of shell initial power is calculated, the collection of Shell resistance is considered when calculating Shell resistance joule heat amount
Skin effect, i.e., on shell section, central current density is small, big by the current density of near surface, according to the physical model of step S1,
After the thermal physical property parameter and skin effect coefficient of shell is determined, the initial temperature of conductor is determined, according to given initial work
Condition parameter calculates the heat amount that iterative solution under GIL pipeline start operating performances goes out corresponding public condition lower conductor.
Step S4:Thermal convection current and the thermal exposure of shell and air are calculated, judges quantity of heat production and the heat dissipation of GIL conductors entirety
Whether amount error is less than program setting error, error be no more than the quantity of heat production of 5%, GIL conductors entirety by conductor quantity of heat production with
The quantity of heat production composition of shell;The heat dissipation of GIL conductors is carried out by the shell directly contacted with outside air, therefore GIL conductors are overall
Heat dissipation capacity be made of the convection current heat output between shell and outside air and radiant heat transfer amount;Calculate the shell being related to and the external world
Whether the thermal physical property parameter of air is the function of temperature, small by the quantity of heat production and heat dissipation capacity error that judge GIL conductors entirety
Judge whether the heat production of GIL conductors entirety and heat dissipation reach balance in setting error, i.e. whether GIL conductors operation has reached
Stable state.
Step S5:If step S4 errors are less than setting error, next step is carried out, otherwise shell initial temperature increases
0.1 DEG C of return to step S3;
Step S6:The thermal convection current between conductor and shell and thermal exposure are calculated, the quantity of heat production and heat dissipation capacity for judging conductor miss
Whether difference is less than setting error;The direct representation of the power attenuation of conductor is the quantity of heat production of conductor, the heat dissipation master of conductor
To be carried out by insulating gas, therefore the heat dissipation capacity of conductor is by the free convection heat transfer amount between conductor and shell and radiant heat transfer amount group
Into the calculating of thermal convection current and thermal exposure between conductor and shell relates generally to the running temperature of conductor and shell, and insulate
The thermal physical property parameters such as the dynamic viscosity of gas, thermal conductivity factor, specific heat at constant pressure, coefficient of cubical expansion, wherein all hot physical property
Parameter is the function of temperature.Judge conductor by the way that whether the quantity of heat production and heat dissipation capacity error that judge conductor are less than setting error
Whether heat production and heat dissipation reach balance, i.e. whether conductor operation has reached stable state.
Step S7:If step S6 errors are less than setting error, calculate and terminate output as a result, otherwise conductor temperature increases
0.1 DEG C of return to step S2.When the quantity of heat production of conductor is less than setting error with heat dissipation capacity error, illustrate that the operation of conductor reaches steady
State, can obtain the running temperature of conductor during stable operation.If the quantity of heat production of conductor is more than setting error with heat dissipation capacity error, i.e.,
Conductor operation is not up to stable state, and need increases conductor temperature at this time is iterated calculating again, until error meets that condition can jump
Go out circulation, close to the temperature of actual conductor and shell when output GIL is stable.
Convection transfer rate of the unknown quantity that GIL physical models are related in the step S1 including air and insulating gas,
Thermal diffusivity, thermal conductivity, dynamic viscosity, specific heat capacity etc. are the thermal physical property parameter of temperature funtion, are the conductor of temperature funtion and outer
The thermal conductivity factor and skin effect coefficient of shell, by using the parameter contacted with temperature, can make result more closing to reality.
In the step S1 initial duty parameter include conductor loading electric current, corridor tube environment temperature, GIL pipelines internal pressure,
Corridor inner air tube flow velocity, GIL pipeline configuration parameters.
In the step S2, conductor considers the collection of conductor there are kelvin effect when calculating conductor resistance joule heat amount
Skin effect;After determining conductor initial temperature, it can determine that conductor initial power is lost according to initial working condition, wherein correlation computations
Formula is:
In formula, RcFor the resistance of conductor, KfcFor the skin effect coefficient of conductor, ρc20For 20 DEG C when conductor D.C. resistance
Rate, TcFor the running temperature of conductor, αc20For the temperature-coefficient of electrical resistance of conductor, ScFor the cross-sectional area of conductor, DcFor conductor diameter,
CcFor conductor wall thickness, PcFor every meter of loss of conductor, I is conductor rated current.
In the step S3, shell considers the collection of shell there are kelvin effect when calculating Shell resistance joule heat amount
Skin effect;After determining shell initial temperature, it can determine that shell initial power is lost according to initial working condition.Wherein correlation computations
Formula is:
In formula, RtFor the resistance of shell, KftFor the skin effect coefficient of shell, ρtaFor 20 DEG C when shell D.C. resistance
Rate, TtFor the running temperature of shell, αtaFor the temperature-coefficient of electrical resistance of shell, StFor the cross-sectional area of shell, DtFor envelope outer diameter,
CtFor shell wall thickness, PtFor every meter of loss of shell, I is shell rated current.
In the step S4, the quantity of heat production of GIL conductors entirety is made of the quantity of heat production of conductor and the quantity of heat production of shell, heat dissipation
Amount is made of the convection current heat output between shell and outside air and radiant heat transfer amount, and correlation computations formula is:
In formula, QtcFor every meter of heat loss through convection amount of shell, QtrFor every meter of heat loss through radiation amount of shell, αaExchange heat for cross-ventilation and be
Number, TaFor ambient air temperature, εtFor inner surface of outer cover blackness, Nu is the nusselt number of outside air, λaFor the heat conduction system of air
Number, GraFor the Prandtl number of air, g is acceleration of gravity, βaFor the coefficient of cubical expansion of air, μaGlued for the power of air
Degree, TdaFor air setting temperature, Δ1For the quantity of heat production and heat dissipation capacity error of GIL conductors.
In the step S6, the power attenuation of conductor is the quantity of heat production of conductor, and the heat dissipation capacity of conductor is by conductor and shell
Between free convection heat transfer amount and radiant heat transfer amount composition, correlation computations formula is:
In formula, QccFor every meter of heat loss through convection amount of conductor, QcrFor every meter of heat loss through radiation amount of conductor, εcIt is black for conductor outside surfaces
Degree, εeFor the suitable blackness of full group object, λeFor equivalent heat conductivity, λ is insulating gas thermal conductivity factor, GrsFor insulating gas lattice
La Xiaofu numbers, PrsFor insulating gas Prandtl number, CpFor insulating gas specific heat at constant pressure, μ is insulating gas viscosity, βsInsulate gas
The coefficient of cubical expansion of body, RtiFor housing interior radius, RcoFor conductor outer radius, TdsFor the setting temperature of insulating gas, Δ2For
The quantity of heat production of conductor and heat dissipation capacity error.
In step S5, the progress that the temperature unit value of increase can have more GIL temperature measuring equipments in actual conditions is configured, and is counted
It is high to calculate precision.
In step S7, the progress that the temperature unit value of increase can have more GIL temperature measuring equipments in actual conditions is configured;It is defeated
The qualitative temperature of the insulating gas of conductor, the temperature of shell and needs when the result gone out runs to stable state for GIL.
GIL running temperature appraisal procedures in the corridor pipe of the present invention, based on law of conservation of energy foundation with for node heat
Network model is transmitted, passes through extra-high voltage GIL thermal characteristics in the corridor pipe that is designed in the MATLAB environment of Windows operating system
MATLAB calculation procedures, can using the GIL relevant featuring parameters under different initial operating modes come to its stable operation when temperature
Carry out assessment calculating.
The present invention carries out assessment calculating by designing MATLAB programs, for the program for predicting GIL thermal characteristics is embedded into GIL
Feasible means are provided in temperature monitoring system.The heat transfer that this method can conveniently try to achieve GIL under different operating modes is special
Property and the temperature of conductor and shell, and then have from bringing into operation to thermal characteristics when stablizing a research well to GIL, its
The calculation procedure of realization, easy to operate, highly practical, calculating speed is fast, can set initial parameter according to different operating mode, to be right
The research of GIL thermal characteristics provides good theoretical foundation, and can be embedded into the temperature monitoring system of GIL as subprogram
In, the reliability of GIL, which plays an important role, to be realized to raising.
Brief description of the drawings
Fig. 1 is the flow diagram of GIL running temperature appraisal procedures in the corridor pipe of the present invention.
Embodiment
The present invention is described in detail with reference to width figure.
The present invention is primarily intended to carry out mould by analytical Calculation to the pipe GIL thermal characteristics heat production of extra-high voltage corridor and diabatic process
Intend, first the GIL structures calculated are carried out simplifying processing:First, ignore power attenuation and the heat transfer of contact part, second,
Only the single-phase GIL pipeline long to one meter carries out the research of thermal characteristics.GIL busbares are powered after operation, not only on conductor there are electric current,
Also have on shell with the big reverse sensing electric current such as load current, therefore conductor and shell can produce power attenuation.Conductor and
Heat transfer between shell is carried out by the convection current and radiation of insulating gas between the two, the heat of shell and outside air
Transmission is carried out by the convection current and radiation of outside air.From law of conservation of energy, during in thermal steady state, conductor
Loss pass to shell in a manner of radiation mode and free convection, GIL overall loss by radiate with free convection in a manner of transmit
To surrounding air, the two is in equilibrium state.The major parameter index of GIL running temperatures includes conductor in this model evaluation corridor pipe
The convection current heat output between the convection current heat output and thermal exposure, shell and air between joule heat waste, conductor and shell with shell
And thermal exposure.
The GIL busbar conservation of energys:
Pc+Pt=Qtc+Qtr (5)
Pc=Qcc+Qcr (6)
Wherein PcAnd PtRespectively every meter of power attenuation of conductor and shell, W/m;QtcFor the free convection of shell and air
Heat exchange amount, W/m;QtrFor the heat loss through radiation amount of outer surface of outer cover, W/m;QccFor conductor and the quantity of heat convection of shell, W/m;Qcr
For the heat loss through radiation amount of conductor outside surfaces, W/m.
The calculating of main assessment parameter:
Pc=I2Rc (7)
Pt=I2Rt (8)
Qtc=αaπDt(Tt-Ta) (11)
Wherein, Tc is the temperature of conductor, and Tt is skin temperature, and Ta is original ambient temperature.It can be obtained from formula, conductor
Temperature, skin temperature, environment temperature and the loss of GIL and heat output are closely bound up.
A kind of GIL running temperatures appraisal procedure schematic diagram in the corridor pipe provided referring to Fig. 1, there is provided GIL operations temperature in corridor pipe
Appraisal procedure is spent, the steady-state operating temperature of extra-high voltage GIL in corridor pipe under different initial working conditions is calculated for assessing, it is assessed
Calculation procedure is as follows:
Step S1:GIL physical models are established according to the related thermal physical property parameter of air, insulating gas, conductor and shell;It is female
Line conductor and shell are heater element, and shell outwardly distributes heat by free convection and radiation.In order to reflect true heat transfer
Process, considers the free convection of the heat transfer mode, i.e. built-in electrical insulation air-flow of free convection and radiation between conductor and shell
The heat radiation and absorption of heat exchange, conductor outside surfaces and inner surface of outer cover, because it was assumed that conductor and shell axial and circumferential temperature
Uniformly, only consider the radial direction heat transfer of conductor and shell in solid domain, be hereby based on law of conservation of energy and establish one-dimensional node
Heat transfer network model.Model is related to resistance joule heat effect, the free convection Laminar Flow of outside air or forces rapids
Flow convection current, built-in electrical insulation gas (such as SF6Gas) electricity, heat, stream, solid more physics such as the Laminar Flow of free convection, radiant heat transfer
, it is a highly complex multiple physical field coupling model.Therefore GIL running temperature parameter index bags in this model evaluation corridor pipe
Include the convection current between the convection current heat output and thermal exposure, shell and air between joule heat waste, conductor and the shell of conductor and shell
Heat output and thermal exposure.
Step S2:Determine conductor initial temperature and initial working condition, calculate the loss of conductor initial power;With it is most of often
Resistance is calculated with cable and is taken as constant difference, and the kelvin effect of conductor resistance is considered when calculating conductor resistance joule heat amount
(i.e. on cross-sectional area of conductor, central current density is small, big by the current density of near surface).According to above-mentioned physical model, it is related to meter
The fluid and solid material attribute of calculation consider the change with local temperature, i.e. outside air, built-in electrical insulation gas, conductor and outer
Shell material matter thermal physical property parameter is the function formula of temperature, and the enclosure material thermal physical property parameter includes viscosity, conduction
Coefficient, it is permanent than pressure, specific heat capacity, thermal coefficient of expansion, so that the numerical value of hot Physical Parameters is actual closer to operation when calculating
Situation;According to the thermal physical property parameter and skin effect coefficient of conductor in actually solving, the initial temperature of conductor is determined, it is assumed that just
Beginning temperature is equal with environment temperature, and calculating GIL pipelines according to given initial duty parameter starts iterative solution under operating condition
Go out the heat amount of corresponding public condition lower conductor;
Step S3:Determine shell initial temperature and initial working condition, calculate the loss of shell initial power;Calculate shell electricity
The kelvin effect of Shell resistance is considered when hindering joule heat amount, i.e., on shell section, central current density is small, by the electricity of near surface
Current density is big, according to the physical model of step S1, after the thermal physical property parameter and skin effect coefficient of shell is determined, determines to lead
The initial temperature (initial temperature is equal with environment temperature) of body, calculates GIL pipelines according to given initial duty parameter and starts work
Iterative solution goes out the heat amount of corresponding public condition lower conductor under condition.
Step S4:Thermal convection current and the thermal exposure of shell and air are calculated, judges quantity of heat production and the heat dissipation of GIL conductors entirety
Whether amount error is less than program setting error (being usually no more than 5%);The quantity of heat production of GIL conductors entirety by conductor quantity of heat production and
The quantity of heat production composition of shell;The heat dissipation of GIL conductors is carried out by the shell directly contacted with outside air, therefore GIL conductors are overall
Heat dissipation capacity be made of the convection current heat output between shell and outside air and radiant heat transfer amount;Calculate the shell being related to and the external world
Whether the thermal physical property parameter of air is the function of temperature, small by the quantity of heat production and heat dissipation capacity error that judge GIL conductors entirety
Judge whether the heat production of GIL conductors entirety and heat dissipation reach balance in setting error, i.e. whether GIL conductors operation has reached
Stable state.
Step S5:If step S4 errors are less than setting error, next step is carried out, otherwise shell initial temperature increases
0.1 DEG C of return to step S3;When the quantity of heat production and heat dissipation capacity error of GIL conductors entirety are less than setting error, illustrate that GIL conductors are transported
Row has reached stable state, can obtain the running temperature of shell during stable operation;If the quantity of heat production and heat dissipation capacity of GIL conductors entirety
Error is more than setting error, i.e. GIL conductors operation is not up to stable state, then needing increases skin temperature is iterated calculating again, directly
Meet that condition is jumped out circulation and carried out in next step to error.
Step S6:The thermal convection current between conductor and shell and thermal exposure are calculated, the quantity of heat production and heat dissipation capacity for judging conductor miss
Whether difference is less than setting error;Step S7:If step S6 errors are less than setting error, calculate and terminate output as a result, otherwise leading
Temperature increases 0.1 DEG C of return to step S2.
GIL running temperature appraisal procedures in the corridor pipe of the present invention, by the MATLAB environment of Windows operating system
Extra-high voltage GIL thermal characteristics MATLAB calculation procedures in the corridor pipe of design, using the GIL relevant featuring parameters under initial operating mode come pair
Temperature during its stable operation carries out assessment calculating.
The above-mentioned initial duty parameter of operating mode include conductor loading electric current, corridor tube environment temperature, GIL pipeline bus internal pressure,
Corridor inner air tube flow velocity, GIL pipeline configuration parameters.
Give the initial parameter value of different operating modes, through can be calculated the joule heat waste of GIL conductors and shell, conductor with it is outer
The convection current heat output and thermal exposure between convection current heat output and thermal exposure, shell and air, the temperature of conductor and shell between shell
Degree.
Verify example:
For verify the above method correctness, using conductor internal diameter as 160mm, conductor wall thickness 20mm, internal diameter of outer cover 860mm,
The GIL of shell wall thickness 16mm conducts heat as experimental subjects for the convection current between the joule heat waste of conductor and shell, conductor and shell
The data such as amount and the convection current heat output between thermal exposure, shell and air and thermal exposure are calculated.Test the extraneous ring of GIL
Border temperature is 25 DEG C, and experiment condition is rated current 8000A.
GIL ambient temperatures are 25 DEG C, it is assumed that the initial temperature of GIL initial launch moment conductors is 24.9 DEG C, shell
Initial temperature be 25 DEG C, the joule heat waste of initial time can be calculated by formula 7~12 conductor and shell is respectively
187.96W/m, 80.47W/m, convection current heat output and thermal exposure between conductor and shell are respectively 2.19 × 10-3W/m、-2.48
×10-2W/m, convection current heat output and thermal exposure between shell and air are 0W/m.Can substantially it be observed by result of calculation, should
Moment, GIL was not stable.The temperature for needing to increase shell or conductor at this time carries out loop iteration calculating, until setting misses
Difference is met:
The joule heat waste of conductor and shell is respectively 177.88W/m, 41.15W/ when GIL stable operations are obtained by calculation
M, convection current heat output and thermal exposure between conductor and shell are respectively 93.77W/m, 75.39W/m, pair between shell and air
It is respectively 167.13W/m, 15.56W/m to spread heat and thermal exposure.By the conductor that is obtained during GIL stable operations and shell
Convection current heat output between convection current heat output and thermal exposure, shell and air and heat radiation between joule heat waste, conductor and shell
The temperature of conductor and shell is respectively 66.7 DEG C, 39.3 DEG C when amount can obtain stable operation.And in actual experiment, GIL is led
The temperature of body and shell is respectively 68.8 DEG C, 40.6 DEG C, and the conductor and the error of skin temperature obtained with this appraisal procedure is
3.2%.It can be seen that this calculating appraisal procedure has higher precision, it is practicable.
The conductor and skin temperature that the assessment of GIL running temperatures appraisal procedure is calculated in the corridor pipe of the present invention can characterize
Conductor and skin temperature during the actual normal operation of GIL busbares, embedded this assessment computation model in GIL temperature monitoring systems,
It can quickly find GIL temperature anomaly phenomenons, and GIL is overhauled, the operational reliability of GIL can be effectively improved.
GIL running temperature appraisal procedures in corridor pipe provided by the invention, assessment calculating is carried out by designing MATLAB programs,
For the program for predicting GIL thermal characteristics is embedded into GIL temperature monitoring systems the feasible means that provide.This method can facilitate
Efficiently try to achieve the heat-transfer character of GIL and the temperature of conductor and shell under different operating modes, and then to GIL from bringing into operation to steady
The thermal characteristics of timing has a research well, its calculation procedure realized, easy to operate, highly practical, calculating speed is fast, can
Initial parameter is set according to different operating modes, provides good theoretical foundation for the research to GIL thermal characteristics, and can make
It is embedded into for subprogram in the temperature monitoring system of GIL, the reliability of GIL, which plays an important role, is realized to raising.
GIL running temperature appraisal procedures in corridor pipe provided by the present invention are described in detail above, and are applied
Specific case is set forth the principle of the present invention and embodiment, and the explanation of above embodiment is only intended to help and understands
The method and its core concept of the present invention;Meanwhile for those of ordinary skill in the art, according to the thought of the present invention, then have
There will be changes in body embodiment and application range, in conclusion this specification content should not be construed to this hair
Bright limitation.